Clinching machine

ABSTRACT

A NAIL CLINCHING MACHINE IN WHICH THE CLINCHING RAM INITIALLY PRESSES AGAINST AND SLIDES RELATIVE TO A TRAVELLING WORKPIECE UNTIL IT ENTERS WITH PRELIMINARY MOVEMENT A HOLE IN WHICH THERE ARE NAILS TO BE CLINCHED. A CONTROL RESPONSIVE TO SUCH PRELIMINARY MOVEMENT ACTUATES THE RAM DRIVE. FOR INITIAL PRESSING AN AIR CYLINDER, AND FOR RAM DRIVE, A HYDRAULIC CYLINDER ARE SHOWN. ALSO, THE AIR CYLINDER ACTING ON THE RAM END AND THE HYDRAULIC CYLINDER LINKED TO THE RAM, AND VENTED INITIALLY TO AVOID RESISTANCE TO THE AIR CYLINDER, ARE SHOWN. A WORKPIECE FEEDER, SHOWN AS A HYDRAULIC CYLINDER, IS STOPPED IN RESPONSE TO THE PRELIMINARY MOVEMENT OF THE RAM. FOR A PAIR OF LATERALLY SPACED CLINCHING RAM THERE ARE TWO SPACED APART FEEDERS, ALL CLINCHING BEING DELAYED UNTIL BOTH FEEDERS STOP BY MEANS OF A LINKED CONTROL SYSTEM. DRIVE OF THE CLINCHING RAM CAN BE ACHIEVED BY A PIVOTED CYLINDER DISPOSED AT AN ANGLE, CONNECTED BY A BELL CRANK TO THE CLINCHER RAM, USED TO ADVANTAGE ON A CANTILEVERED CLINCHER EXTENDING INTO THE INTERIOR OF A PALLET FOR CLINCHING NAILS IN THE MIDDLE STRINGER.

June 8, 1971 L. HEIN CLINCHING MACHINE 3 Sheets-Sheet 1 Filed July 28,1969 June 8, 1971 L. HEIN CLINCHING MACHINE 3 Sheets-Sheet E Filed July28, 1969 FIG. 3

June 8, 1971 L. HEIN CLINCHING MACHINE 3 Sheets-Sheet 3 Filed July 28,1969 United States Patent 3,583,053 CLINCIHNG MACHINE Leo Hein,Burlington, C0nn., assignor to Clinch-Tite Corporation, Berwyn, Pa.Filed July 28, 1969, Ser. No. 845,479 Int. Cl. B25c 7/00 US. Cl. 29-20011 Claims ABSTRACT OF THE DISCLOSURE A nail clinching machine in whichthe clinching ram initially presses against and slides relative to atravelling workpiece until it enters with preliminary movement a hole inwhich there are nails to be clinched. A control responsive to suchpreliminary movement actuates the ram drive. For initial pressing an aircylinder, and for ram drive, a hydraulic cylinder are shown. Also, theair cylinder acting on the ram end and the hydraulic cylinder linked tothe ram, and vented initially to avoid resistance to the air cylinder,are shown. A workpiece feeder, shown as a hydraulic cylinder, is stoppedin response to the preliminary movement of the ram. For a pair oflaterally spaced clinching rams there are two spaced apart feeders, allclinching being delayed until both feeders stop by means of a linkedcontrol system. Drive of the clinching ram can be achieved by a pivotedcylinder disposed at an angle, connected by a bell-crank to the clincherram, used to advantage on a cantilevered clincher extending into theinterior of a pallet for clinching nails in the middle stringer.

This invention relates to clinching machines of the type in which, aftera workpiece is moved to align its hole with the ram, the ram forces itsway through the hole to clinch nails protruding therein. Of particularconcern are machines using a plurality of simultaneously actuated ramsincluding cantilever-mounted interior-fitting middle rams, for clinchingthe nails in elongated stringers of pallets.

A principal object of the invention is to provide fast machines and oneswhich are simple in construction and operation, require little operatorskill, and are useful with workpieces of various sizes.

A principal feature of the invention is a control system for themovements of the machine. In this system the clinching ram (feels) forthe hole it is to enter, this being achieved by a pressing means thaturges the clinching ram against the workpiece with pressure sufficientlylight to permit the workpiece to slide past the ram. This pressurecauses preliminary movement of the ram into a workpiece hole when thelatter comes into registry with the ram. A ram drive control systemresponsive to this preliminary movement activates the drive device toforce the ram to clinch the nails.

Preferred embodiments of the invention feature the use of air cylindersfor creating the initial pressure on the ram, hydraulic cylinders forfinally actuating the ram and hydraulic cylinders for feeding theworkpieces, all interconnected through a control system that responds tothe preliminary movement of the rams.

Preferred embodiments also feature a ram drive including a fluidcylinder set at an angle to the ram, connected by a bell crank, whichoccupies no more lateral space than that occupied by the ram. It is usedadvantageously in a cantilevered assembly for fitting within pallets.

These and numerous other objects and features will be understood in thelight of the following description of a preferred embodiment, inconnection with the drawings wherein:

Patented June 8, 1971 FIG. 1 is a perspective View, in somewhatschematic form, of a preferred embodiment of the clinching machine,showing a pallet (shown partly broken away) being withdrawn;

FIG. 2 is a perspective view, partly broken away of the clinching rampressing and drive devices for one side of the machine;

FIGS. 3 and 4 are plan and front elevation views respectively of themachine of FIG. l;

FIG. 5 is a plan view on an enlarged scale, of a portion of the machineshowing schematically the control system;

FIG. 6 is a diagrammatic view of the relation of the clinching ram tothe pallet during various stages of the operation of the machine.

Referring to the drawings there is shown a clinching machine for use infabricating pallets.

Supports 10 and side rails 12 define guides for movement of the pallet14 in the longitudinal direction, parallel to outside stringers 16 andmiddle stringer 18 of the pallet. Deck boards 20 and bottom boards 22have previously been nailed to these stringers and the nails 24 protrudeinto lateral holes 26 in the stringers. The purpose of the machine is toclinch these nails.

To this end there are laterally aligned openings 27 in the side rails 12through which clinching rams or mandrels 28 are arranged to be driven,to force their way through holes 26. Likewise a cantilever support 30fixed at the rear of the machine is sized (by virtue of the compact ramdrive mechanism to be described) to protrude forwardly inside thepallet, between the deck boards, bottom boards and stringers, forclinching the nails of the middle stringer 18. This mechanism includesram 32 mounted on the end of the cantilever.

It can thus be seen that sliding of the pallet from a rearward positionforwardly, in the direction of the arrow A, will bring the holes 26 ofthe stringers in alignment with the openings 27 in the side rails andthe associated clinching rams 28.

The control system feature of this embodiment employs air cylinders 34,one associated with each outside ram 28. The rams are of rod formslideably mounted in slide bearings 36, 38. The forward end 40 of theram is shaped to clinch the nails and the rearward ends 42 of the ramsare exposed. The air cylinders are mounted so that their pistons 35 canengage the rearward ram ends 42 when the rams are in their retractedpositions.

The driving device for each ram, including middle ram 32, comprises ahydraulic cylinder 43 set substantially at a right angle a to the axis Rof the ram. The cylinder housing end is pivotally mounted to the frameat 44 while the piston end is pivotally connected at 46 to one arm ofbell crank 48. This bell crank is pivoted to the frame at 50 and has itsother end of the form of a yoke 52. The upper and lower bars of thisyoke are fitted into matching slots 54 of adaptor 56 which is fixed tothe ram 28 or 32. The ends of the yoke bars are of circular form inplan, and thus engage the front and rear walls of the adaptor slots witha pivotal-sliding contact. It will thus be seen that movement of thepiston 43a of the hydraulic cylinder imparts axial movement to the rams.

Referring e.g. to FIGS. 2 and 5, three limit switches X, Y and Z areassociated with the outside rams 28. Switch X is arranged to detect thepreliminary movement of the rams 28. This occurs when the ram, pressedforward by air cylinder 34 and sliding on surface 16a of stringer 16(FIG. 6, position I) registers with hole 26 in the stringer, and movesinto the hole under the influence of air cylinder 34 (FIG. 6, positionII). Switch X then activates the hydraulic cylinder 43. Switch Y detectscompletion of the travel of the ram (FIG. 6, position III) at whichclinching of nail 24 is assured. This reverses the movement of hydrauliccylinder 43 and releases the air cylinder for return. Switch Z detectscompletion of the return travel of the ram beyond the plane of the side16a of the stringer (FIG. 6, position IV). This vents both ends of thehydraulic cylinder and also maintains air cylinder 34 under ventedcondition. It also reinitiates movement of the feeder to be described,after which air pressure is reapplied to the air cylinder, the hydrauliccylinder 43 remaining vented, and the ram is again pressed against theside of the stringer (FIG. 6, position V) sliding therealong until thenext hole is encountered.

[If there were but one ram 28 the above would be the entire sequence.According to the invention, when two outside rams 28 are employed, therams are axially aligned for oppositemovement, and the drive of thecylinders 43 is delayed until both rams undergo the preliminary movementillustrated in FIG. 6, this event actuating the drive. Thereupon bothare activated, countering the force of each other.

Referring e.g. to FIGS. 1 and 3, the particular angled relationship ofhydraulic cylinder 43 and middle ram 32 with the intermediate bell crank48, is so compact that it can be employed in a cantilever structure toenter the interior of conventional pallets (e.g. pallets having 2 x 4"stringers with deck and bottom boards secured directly thereto, withspacings on the order of 20 or less between stringers). As shown, no aircylinders are associated with such middle rams, these being aligned withand activated at the time of actuation of the outer rams, 28'.

The feeder system in the preferred embodiment of the drawings also playsa part in the control system. The feeder here is comprised of two cablecylinders 60, one mounted along each side rail 12. These, as is known,are hydraulic devices having cylinders 62' of a length approximating thedesired length of travel, a short length piston 64, and a cable. Thecable extends from one side of the piston through the hydraulic fluid,out one end of the cylinder, around a pulley 68, back the length of thecylinder, around a second pulley 70, into the opposite end of thecylinder and through the fluid to the other side of the piston. Apallet-dragging arm 72 is attached to each cable and protrudes toengage, near the adjacent corner, the rear of the pallet (FIG. 5) topull it forward. Front and rear limit switches, U and V (FIGS. 3, 5) areassociated with the cable cylinder 60 to limit its movement.

In this embodiment the hydraulic control valves are constructed andarranged so that whenever preliminary movement of one of the side rams28 occurs, the activation of its switch X stops hydraulic fluid flow tothe cable cylinder 60 on the corresponding side, but flow continues tothe cable cylinder 60 on the other side. This continued movement of theother side adjusts the position of the pallet on the machine, withsliding of the other ram on the stringer until it enters a hole, withthe preliminary movement that has been mentioned. Activation of its Xswitch secures the corresponding cable cylinder, thus stopping thepallet, and X also activates all rams. The clinching cycle activatesswitches Y and the return movement activates switches Z. The latterreactivate the two cable cylinders, and after a short delay allowing forthe pallet to be moved so the holes no longer align with the rams, aircylinders 34- are re-energized, pressing the rams forward to permittheir sliding movement along the sides of the stringers.

Numerous variations of the specific details are within the spirit andscope of the invention.

What I claim is:

1. In a clinching machine having a ram that is forced by a drive deviceinto holes in the side of an elongated workpiece to secure fasteningelements therein, and means permitting longitudinal feeding movement ofthe workpiece sideways relative to the ram, the improvement comprisingpressing means adapted to urge the ram against the side of the workpiecewith pressure sufficiently light to permit the workpiece in its feedingmovement to slide past said ram, said pressing means adapted to movesaid ram preliminarily into a hole in the workpiece when the holeregisters with the ram, and a ram drive control system responsive tosaid preliminary movement to activate said drive device to force saidram to clinch said fastening elements.

2. The clinching machine of claim 1 wherein said pressing meanscomprises an air cylinder.

3. The clinching machine of claim 2 in which said ram comprises a rodform member haing a first end shaped to enter the hole in the workpiece,and there are spaced apart bearings slidably mounting said ram with thesecond end of said ram exposed, wherein said air cylinder is arranged toengage said second end of said ram to press it forwardly and said drivedevice for said ram is connected to the rod-form member intermediate itsends.

4. The clinching machine of claim 1 wherein said drive device comprisesa hydraulic cylinder linked without lost motion to said ram, saidcylinder connectable to a source of pressurized hydraulic fluid througha valve, said valve having a neutral position venting the cylinder,allowing movement of its piston in response to said preliminary movementof said ram, and said control system in response to said preliminarymovement adapted to move said valve first to a forward positiondirecting fluid to said cylinder to drive said ram forward forclinching, then to a rearward position to cause said ram to retract,then to said neutral position to permit said pressing means to actagain.

5. The clinching machine of claim 4 wherein said hydraulic cylinder hasa suflicient return stroke to disengage said ram from said workpiece andsaid control system is adapted to reactivate said pressing means to urgesaid ram against the side of said workpiece only after further feedingmovement of said workpiece has occurred.

6. The clinching machine of claim 1 wherein said means permittingrelative feeding movement of the workpiece sideways relative to the ramincludes a driven feeder member and said control system comprises afirst control means responsive to said preliminary movement of said ramto stop said feeder member and to activate said ram drive device and asecond control means responsive to the return of said ram drive deviceto start said feeder member to initiate another cycle.

7. The clinching machine of claim 6 comprising a supply of pressurizedhydraulic fluid, said feeder comprising a hydraulic piston and said ramdrive device comprising a hydraulic piston, said control system operableto connect one and then the other of said pistons to be driven by saidhydraulic fluid.

8. The clinchingmachine of claim 6 having two clincher rams spaced apartin the direction transverse to the feeding direction of said workpiece,adapted to act simultaneously to clinch nails in holes on opposite sidesof the workpiece, each of said clinching rams having a drive device andpresser means in accordance with claim 1, and there being two separatefeeder members in accordance with claim 6 associated with the respectiveclinching rams, said control systems adapted to permit each feedermemher to operate until said preliminary movement of its respective ramoccurs, and said control system adapted to activate the ram drive deviceonly when said preliminary movement of both of said rams has occurred.

9. The clinching machine of claim 8 adapted for the fabrication ofpallets in which said two clincher rams are directed towards each otherto engage the outer stringers of the pallet and a third clincher ram ismounted on a cantilever support and extends into the pallet to act upona middle stringers between said outside stringers, wherein the drivedevice for each of said rams comprises a respective hydraulic cylinderand said control system is adapted to direct pressurized hydraulic fluidto each of said cylinders to cause simultaneous action thereof upon saidpreliminary movement of the two rams into the outside stringers.

10. In a clincher assembly comprising an elongated clinching rodslidably mounted for entering a hole under the influence of a drivedevice for clinching nails in the hole, the improvement wherein saiddrive device comprises a fluid actuated cylinder disposed at asubstantial angle to the line of movement of said clinching rod, saidcylinder pivoted at one end to stationary structure and pivoted at theother to one of the arms of a bell crank, the other end of said bellcrank pivotally connected to said clinching rod in a manner to permitaxial movement of the latter.

11. The clincher assembly of claim 10 mounted on a cantilever support ina pallet clinching machine, adapted for insertion into the interior of apallet for clinching nails in middle stringers thereof, said fluidactuated cylinder References Cited UNITED STATES PATENTS 7/1962 Hadnagy227-69 7/1965 Hadnagy 227-27 0 FRANK T. YOST, Primary Examiner US. Cl.X.R.

